ocw.mit.edu
Unknown
MIT OpenCourseWare (OCW) provides free, publicly accessible course materials from MIT—lecture notes, assignments, exams, and video lectures across disciplines. It includes math courses covering topics like set theory and cardinality, with downloadable resources and searchable course pages.
More resources on Cardinality
nLab: Cardinality
Advanced category-theoretic perspective
Stanford Encyclopedia of Philosophy: Set Theory
Comprehensive entry on set theory including cardinality
Hilbert's Infinite Hotel Paradox
Numberphile on countability
How To Count Past Infinity
Vsauce explains countable and uncountable infinities
Set Theory
Learn set theory & explore cardinality with Dr. Trefor Bazett's course. Master the fundamentals through this accessible YouTube playlist!
mathworld.wolfram.com
MathWorld is Wolfram's comprehensive online math encyclopedia with in-depth articles on topics across mathematics, including cardinality. Each article offers clear definitions, explanations, formulas, examples, and diagrams to help you understand the concept.